US3387138A - Radiant energy sensitive electronic curve follower - Google Patents

Radiant energy sensitive electronic curve follower Download PDF

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Publication number
US3387138A
US3387138A US377749A US37774964A US3387138A US 3387138 A US3387138 A US 3387138A US 377749 A US377749 A US 377749A US 37774964 A US37774964 A US 37774964A US 3387138 A US3387138 A US 3387138A
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United States
Prior art keywords
line
black
edge
spot
single shot
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US377749A
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English (en)
Inventor
Evon C Greanias
Philip F Meagher
Charles E Smyrk
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
International Business Machines Corp
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International Business Machines Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US248585A external-priority patent/US3229100A/en
Priority claimed from US305254A external-priority patent/US3267285A/en
Priority to GB46116/63A priority Critical patent/GB996509A/en
Priority to DEJ24971A priority patent/DE1205745B/de
Priority to NL63302499A priority patent/NL145071B/xx
Priority to NL302499D priority patent/NL302499A/xx
Priority to BE641906D priority patent/BE641906A/fr
Priority to CH1606263A priority patent/CH411421A/de
Priority to FR958805A priority patent/FR1393325A/fr
Priority to SE14630/63A priority patent/SE313685B/xx
Priority to US377749A priority patent/US3387138A/en
Application filed by International Business Machines Corp filed Critical International Business Machines Corp
Priority to GB32655/64A priority patent/GB1008560A/en
Priority to FR986103A priority patent/FR1409557A/fr
Priority to DEJ26474A priority patent/DE1211009B/de
Priority to GB19554/65A priority patent/GB1039948A/en
Priority to GB19553/65A priority patent/GB1044246A/en
Priority to FR21719A priority patent/FR1445798A/fr
Publication of US3387138A publication Critical patent/US3387138A/en
Application granted granted Critical
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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V30/00—Character recognition; Recognising digital ink; Document-oriented image-based pattern recognition
    • G06V30/10—Character recognition
    • G06V30/14—Image acquisition
    • G06V30/144—Image acquisition using a slot moved over the image; using discrete sensing elements at predetermined points; using automatic curve following means
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K11/00—Methods or arrangements for graph-reading or for converting the pattern of mechanical parameters, e.g. force or presence, into electrical signal
    • G06K11/02—Automatic curve followers, i.e. arrangements in which an exploring member or beam is forced to follow the curve
    • G06K11/04—Automatic curve followers, i.e. arrangements in which an exploring member or beam is forced to follow the curve using an auxiliary scanning pattern
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G1/00—Control arrangements or circuits, of interest only in connection with cathode-ray tube indicators; General aspects or details, e.g. selection emphasis on particular characters, dashed line or dotted line generation; Preprocessing of data
    • G09G1/06—Control arrangements or circuits, of interest only in connection with cathode-ray tube indicators; General aspects or details, e.g. selection emphasis on particular characters, dashed line or dotted line generation; Preprocessing of data using single beam tubes, e.g. three-dimensional or perspective representation, rotation or translation of display pattern, hidden lines, shadows
    • G09G1/08—Control arrangements or circuits, of interest only in connection with cathode-ray tube indicators; General aspects or details, e.g. selection emphasis on particular characters, dashed line or dotted line generation; Preprocessing of data using single beam tubes, e.g. three-dimensional or perspective representation, rotation or translation of display pattern, hidden lines, shadows the beam directly tracing characters, the information to be displayed controlling the deflection and the intensity as a function of time in two spatial co-ordinates, e.g. according to a cartesian co-ordinate system

Definitions

  • ABSTRACT OF THE DISCLOSURE An electronic curve follower of the type wherein the radius of the scanning circle is reduced upon the detection of black and provides improved criteria for controlling the radius reducing attenuator. Such provision is primarily accomplished by delaying the operation of the attenuator for a fixed interval after the scanning spot enters the area of the line. During this interval, the photo-reflected signal is analyzed to ascertain that the scanning spot did enter the line. After such ascertaining, the attenuator is operated.
  • This invention relates to electronic servo apparatus, and more particularly to an electronic servo apparatus which is particularlyadapted to follow the configuration of an imprinted lexical symbol and produce shape-manifesting signals especially suited for processing in a character recognition apparatus.
  • scanning devices for scanning imprinted lexical symbols may vary greatly in their structural details, as well as in their modes of operation, they all operate in either a fixed or variable scan pattern.
  • the fixed pattern scanners of which the raster scanner is most typical, traverse each symbol or character in an invariable path and produce pulses spaced in time to represent the blacks of the character relative to the white background. These pulses, when correlated with the scanning pattern, represent the shape of the symbol in a binary rotation.
  • the variable scan pattern devices are best illustrated by the curve follower, which traces the character shape, thus following a different path for each different symbol. Curve followers yield time variant analog waveforms representing the successive orthogonal (or polar) coordinates of the trace.
  • the present invention constitutes an improvement in curve followers which permits not only an improved follower action, but also yields binary information signals in addition to the analog information signals. It thus combines the features of both a fixed pattern scanner and a variable pattern scanner.
  • the binary signals provide the basis for ready recognition of features in lexical symbols such as T joints, corners, line ends, line breaks, and other abrupt discontinuities in the symbols.
  • an object of this invention to provide a scanning device for imprinted line patterns which produces both analog and binary-like signals which manifest of the configuration of the pattern traced.
  • a further object is to provide an electronic curve follower apparatus which follows the outline of an imprinted lexical symbol and produces time variant analog waveforms representing the shape of the symbol as well as black and white manifesting symbols representing predetermined features within the symbol.
  • An even further object is to provide an electronic curve follower for following the outline of an imprinted lexical symbol wherein an illuminating spot is animated in an overlapping series of circular paths straddling the line and having a diameter greater than the line thickness in such manner as to follow on a single edge of the line in a closed trace.
  • Another object of the invention is to provide an electronic curve follower for following the edge of a line with a spot of light animated in a series of overlapping circular patterns having a combined dimension greater than the thickness of the line and straddling the line wherein details on the other side of the line may be detected.
  • Yet another object of the invention is to provide an electronic curve follower for following the edge of a line with a spot of light animated in a series of overlapping circular patterns having a diameter greater than the thickness of the line and disposed to straddle the line wherein the transitional illumination at the line edge initiates a timing action which is utilized only if the transition is followed by blackness having a predetermined persistence and quality.
  • Still another object is to provide an electronic curve follower in accordance with the foregoing object in which the line quality is tested with at least two different standards in accordance with the previous history of the beam intercepts with the line.
  • a further object is to provide an electronic curve follower for following the edge of a line in which an artificial line intercept signal is generated upon the failure of the beam to intercept the line within a prescribed interval to cause the tracing beam to bridge imperfections in the line.
  • FIG. 1 is a schematic block diagram of the electronic curve follower embodying the improvements constituting the present invention.
  • FIG. 2 shows the details of the block 100 of FIG. 1 and specifies the improvements that distinguish the present invention over prior curve followers.
  • FIG. 1 there is shown a curve follower, which, except for circuits contained in the box 100, is generically similar to that shown in co-pending applications, Ser. Nos. 248,585 (filed Dec. 31, 1962), issued on Jan. 11, 1966 as US. Patent No. 3,229,100 to Evon C. Greanias for Electronic Servo System, and assigned to the Inter national Business Machines Corporation, and 306,119 (filed Sept. 3, 1963) and issued on Nov. 29, 1966 as US. Patent No. 3,289,004 to Evon C. Greanias and Philip F. Meagher for Photosensitive Electronic Servo Apparatus For Curve Following, and also assigned to the International Business Machines Corporation.
  • the document 213, containing the lexical symbol 213a imprinted thereon in contrasting ink is illuminated solely by the light from the cathode ray tube 210, whose sharply focused spot of light on the fluorescent tube face is imaged on the document by suit- 2051:.
  • sinusoidal oscillations originating in oscillator 200, and phase shifted respectively by and 100 in phase shifters 201 and 202 to achieve a difference of 90 in phase provide sine and cosine waveforms having the same amplitude to the attenuators 203 and 205 as described in patent 3,267,285, the circle size control 250 functions to adjust the amplitude of the oscillator 200 as a function of the character size measured in a first pass around the character.
  • waveform is the sine and which the cosine.
  • the im ortant consideration is that these waveforms have the sinusoidal configuration, the same frequency and amplitude, and that they have a relative phase displacement of 90.
  • waveforms having this relationship are applied through the summing amplifiers 208 and 209 to the deflection circuits of the cathode ray tube 210, the electron beam will be animated to trace a circular path on the screen, the diameter of which is proportional to the amplitude of the waveforms.
  • the photomultiplier 214 will detect this change in the reflected light and initiate controls within the circuit box 100 to reduce the gain of the attenuators 203 and 205 for the requisite time. While the action of the attenuators in producing a following action will be discussed in detail, it will be intuitively appreciated that with no attenuation a circular path will be traced. If, during that period in the circular rotation when the beam is traveling substantially parallel to the line edge, the Waveforms are attenuated, then lesser amplitude waveforms will be available for integration. The center of the circle will thus precess along the line by an amount equal to the lesser integrated energy. The circuits in the box 100 control the duration and timing of this attenuation.
  • the diameter of the circularpattern when imaged on the symbol line, is .040 with respect to a line thickness of perhaps .015".
  • the circular pattern is referenced to a single edge of the line only, the center thereof lying a fixed distance from the edge of the line, and within the line.
  • the follower in tracing a horizontal straight line, follows first on the top edge of the line attenuates at the bottom of the curve to produce a series of connected substantially circular traces. If the beam revolves counter-clockwise, the gross migrational movement will be from right to left. When the trace reaches the left end of the line, it will switch and follow the bottom edge of the line from left to right, now attenuating the waveforms at the top of the circular swing.
  • the filters 246 and 247 are provided to filter out the high frequency sinusoidal waveforms, leaving only the slowly varying potentials which represent the orthogonal coordinates of the character trace with respect to time.
  • These time variant waveforms appearing at the hubs 246a and 247a are dynamically analyzed to provide the recognition of the symbol traced. In the prior curve followers, these waveforms were the sole source of raw data for recognition purposes.
  • the circuits within the box 100 include detection means for giving sense to black return signals from the off-side of the line.
  • the photodetec-tor 214 produces black and white manifesting signals. These signals are binary, or digital, in nature, in that they are either present or absent, as opposed to an analog signal which is ever present, but varies in magnitude to manifest its information. By relating the sequence of black and white signal returns to the periodicity of the oscillator 200 and to the line edge upon which the follower is operating, the circuits 100 give sense to binary signals originating in the photodetector. The extra binary output appears at the outlet hub 10%.
  • the tracing beam 50 will proceed from A to B, revolving in the white background about the center 0 with a radius of .020".
  • the intercept of the tracing spot with the black line edge initiates the 90 time delay before the start of the attenuation period.
  • Rotation from B to C within the black of the line has no affect upon the follower action, nor does the exit from the line at C.
  • the 90 delay interval expires at point D.
  • the waveforms are attenuated by one half, and the timing of the attenuation period begun.
  • Each subsequent cycle is a mere repeat of that just traced with an attenuation of the beam to one half amplitude for 60 starting 90 after line edge intercept.
  • the instantaneous successive shifts of the centers of rotation through O O O 0 etc. causes the gross migration of the beam to the left.
  • the high frequency sinusoidal waveforms are filtered out (by filters 246 and 247, FIG. 1), the remaining slowly variant waveforms will represent the orthogonal displacements of the locus of the odd-numbered centers of rotation 0 O 0 etc.
  • the specific parameters employed in the preferred embodiment produce a stable following action in which the centers of rotation of the large trace are located within the line 51 at a distance of .010 from the edge 51a followed. Derivatively, therefore, the trace extends .010" above the line edge 51a, and below the line edge 51b by .014.
  • the beam will also intercept the followed edge 51a at an angle of 60, and the direction of migration will be 30 counter-clockwise relative to the line of intercept.
  • the beam circle will move .010" towards 5 oclock.
  • the next intercept will occur at 8 oclock moving the center downward and to the left, placing it almost in the line edge.
  • the next intercept at 9 oclock moves the center into the edge of the line and to the left. After several more intercepts, the beam center will achieve its stable following position of .010 from the line edge and successive intercepts at 10 oclock.
  • the circularly animated spot of light will find no intercept at 10 oclock. Instead, the intercept will occur at 4 oclock (approximately) which is displaced by 180. This, after a special test cycle, will cause the horizontal integrator to receive voltage increments of opposite polarity and move the tracing beam from right to left instead of its former direction of movement.
  • the rotating spot of light intercepts the black of the line edge (under certain restraints to be discussed), it will initiate a follower action along that edge seeking the stable following conditions above set forth.
  • the follower will normally intercept the horizontal edge at 10 oclock.
  • the first intercept with the vertical edge might occur between slightly after 10 oclock or as early as 11:40 (counterclockwise rotation), depending on whether the tracing beam just reached the vertical edge, or just missed it in v the cycle preceding.
  • R radius of larger circular trace
  • K the attenuation factor
  • a 60 intercept angle is sufiiciently close to the normal to produce a signal which is imperceptively different from the normal intercept while preserving a sharp transition.
  • the preferred embodiment employs 60.
  • the choice of parameters is largely empirical and obtained by experimentation with a large sample of characters.
  • the 90 delay, 60 attenuation angle, .040 radius and an attenuation factor of .5 has been found to be satisfactory for the average handwritten numeral, written with a pencil or ball point pen on good grade paper stock. Other specimens made with liquid ink pens on absorbent paper would require a different set of parameters for stable operation.
  • FIG. 2 shows the circuit component enclosed within the box 100 of FIG. 1, it will be appreciated that this circuits prime functions are timing and some simple logic.
  • point B FIG. 3
  • the photomultiplier 214 When at point B (FIG. 3) the tracing beam intercepts the line edge 51a, the photomultiplier 214 will experience a sharp diminution in the incidental light and will yield a corresponding electrical signal to the video amplifier 10.
  • the amplified response is clipped by clipper 11 and passed by the video AND gate 12 (now open) to the AND gates 13 and 14 in parallel. Because of conditions precedent (to be explained), only the AND gate 13 will be active to pass the clipped white-to-black video response to fire single shot 15.
  • This single shot like all other singe shots in the circuit, has a G and a P output tap.
  • the G tap is a gating or continuous output for the duration of the astable operation of the single shot.
  • the P, or pulse output is a diode-capacitator coupled output so as to yield a response only when the single shot turns off.
  • the gating pulse from single shot 15 feeds AND gate 16, rendering it receptive to the amplified video signals from video amplifier 10.
  • AND gate 16 thus activated, passes the amplified video signals to the normal video evaluator 17. Since the tracing beam is now passing within the black of the line 51 in the region from B to C (FIG. 3), the video evaluator 117 is testing the video signal for blackness. This test obviates false black response from a speck or smudge, and seeks to establish the black hit as a legitimate line hit.
  • the normal video evaluator 17 includes an integrating circuit and a latch with a minimum threshold voltage. If the amplified black video signal is sufficiently strong and persistent, the capacitor in the integrating circuit within the evaluator will accumulate charge to achieve a voltage level sufiicient to set the latch to register the satisfactory test. The latch set condition appears as a signal on line 17a. The latch is reset by a pulse or signal applied to line 17b which also discharges the integrator circuit to destroy any accumulated charge.
  • the single shot 26 will initiate an artificial attenuation of the beam to cause the trace to move ahead in an effort to bridge the break. If, at the end of the period of single shot 26 neither the normal video evaluator 17 nor the early video evaluator 29 has been satisfied, then their respective latches will remain reset.
  • the respective inverters 31 and 32 will yield potentials to AND gate 33 which also receives further potentials from the set side of flip-flop 34 and inverter 23 to fully energize the gate when the pulse output from single shot 26 occurs.
  • the response of AND gate 33 resets Hip-Hop 34 and through OR 20 fires single shot 21 to produce the artificial attenuation.
  • the deep follower produces information with respect to the reverse side of the line. T joints for example, may thus be detected.
  • This function is achieved by AND gate 35 which receives inputs from video amplifier 10 and single shot 21. Since single shot 21 fires only on the side opposite to the edge being followed, then it will pass the video only during this time. Thus, if the apparatus were following the upper edge of the horizontal bar of a T, the beam, when it was rotating about the junction of the horizontal and vertical bars, would yield three black intercepts during a single rotation.
  • the AND gate would be open for the 60 at the bottom of the trace, corresponding to the are from D to E (FIG. 3).
  • An electronic curve follower for following a line pattern comprising:
  • the electronic curve follower of claim 1 in which the means under control of said radiant energy responsive means for reducing the diameter of said circular path includes timing means for producing a delay following the passage of said spot into one edge of said line equal to the time required for the spot to rotate in said circular path, and the period in which the spot rotates at the lesser diameter is equal to the time required for the spot to rotate 60 at the greater diameter.
  • the electronic curve follower of claim 1 wherein the animating means comprises a cathode ray tube, including beam deflection means, together with means for applying sinusoidal waveforms in quadrature to the defiection means.
  • a curve follower for following a line pattern comprising:
  • the said spot having a maximum dimension substantially smaller than the thickness of the line defining the pattern
  • testing means connected to said radiation responsive means for testing the quantity and persistence of the energy absorbed by said line and yielding a control signal upon the occurrence of a predetermined quantity and persistence of absorption
  • said testing means includes integrating means and a latch, the said integrating means being operative responsive to said radiation responsive means to accumulate a. voltage charge in response to the lack of energy incident upon said radiation detection means, manifesting an energy absorption by said line pattern, and said latch being operative responsive to the accumulation of a given charge in said integrator.
  • ' (a) means including :a cathode ray tube for imaging a concentrated spot of light upon the line pattern;
  • (0) photodetection means for detecting the quantity of light reflected from said line pattern as said spot moves within and without said line;
  • testing means connected to said photodetector means and operative responsive to the output thereof to test the absorption of said line of th light energy from said spot and yielding a control signal upon the measurement of a given quantity of energy;
  • (e) means responsive jointly to said control signal and to the entrance of said spot within said line, as detected by said photodetector to instantaneously shift the center of rotation of the circular path and reduce the radius thereof for a given time duration beginning a fixed delay following the entrance of the spot into said line.
  • An electronic curve follower for following a line pattern comprising:
  • a cathode ray tube including beam focusing and beam deflection means for producing a movable luminous spot on the face of the tube;
  • Attenuating means for selectively setting the amplitude of said waveforms at one of two levels
  • photodeteotor means for detecting the absorption of energy from said imaged spot by said line pattern as said spot moves within :and without said line;
  • first testing means connected to said photodetector and operative to measure the quality of the line by measuring the energy absorption by said line and yielding a first control signal upon the measurement of a given absorption
  • timing means operative responsive to the detection by said photodeteotor of the entrance of said spot into said line for initiating a first timing interval T
  • means for rendering said first testing means operative during said period T means responsive at the end of the period T to said first control signal for initiating a succession of timing periods T T T and T (1) means operative during the period T for controlling said attenuating means to reduce the amplitude of said sinusoidal waveforms;
  • (m) means operative during the period T for rendering the response of said phot-odetector means ineifectual to produce a reinitiation of the timing period T
  • (n) means operative during the period T; for rendering said second testing means operative;
  • (0) means operative responsive at the end of the T period for initiating a single succession of timing periods T T T and T upon the absence of control signals from said first and second testing means.
  • the curve follower of claim 9 having additional means operative during the period T for rendering said photodetector means operative to yield signals manifestive of discontinuities in that edge of the line opposite to the edge that initiated the timing period T 11.
  • the curve follower of Claim 9 wherein the timing interval T is equal to of circular movement of said spot, T equals 60, T equals T equals 60, and T equals 120.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Multimedia (AREA)
  • Remote Sensing (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Artificial Intelligence (AREA)
  • Controls And Circuits For Display Device (AREA)
  • Character Discrimination (AREA)
  • Machine Tool Copy Controls (AREA)
  • Character Input (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)
  • Studio Circuits (AREA)
  • Facsimile Scanning Arrangements (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
US377749A 1962-12-31 1964-06-24 Radiant energy sensitive electronic curve follower Expired - Lifetime US3387138A (en)

Priority Applications (15)

Application Number Priority Date Filing Date Title
GB46116/63A GB996509A (en) 1962-12-31 1963-11-22 Electronic servo systems for following the contours of line patterns
DEJ24971A DE1205745B (de) 1962-12-31 1963-12-19 Vorrichtung zur optischen Abtastung von Zeichen
NL63302499A NL145071B (nl) 1962-12-31 1963-12-23 Inrichting voor het volgen van lijncontouren.
NL302499D NL302499A (fr) 1962-12-31 1963-12-23
BE641906D BE641906A (fr) 1962-12-31 1963-12-27
CH1606263A CH411421A (de) 1962-12-31 1963-12-30 Vorrichtung zum optischen Abtasten von Zeichen mittels einer Kathodenstrahlröhre
FR958805A FR1393325A (fr) 1962-12-31 1963-12-30 Servo-mécanisme électronique
SE14630/63A SE313685B (fr) 1962-12-31 1963-12-31
US377749A US3387138A (en) 1962-12-31 1964-06-24 Radiant energy sensitive electronic curve follower
GB32655/64A GB1008560A (en) 1962-12-31 1964-08-11 Electronic servo apparatus
FR986103A FR1409557A (fr) 1962-12-31 1964-08-25 Appareil suiveur de courbes
DEJ26474A DE1211009B (de) 1962-12-31 1964-08-29 Vorrichtung zur optischen Abtastung von Zeichen zu deren maschineller Erkennung
GB19554/65A GB1039948A (en) 1962-12-31 1965-05-10 Improvements in or relating to electronic servo apparatus for following the contour of line patterns
GB19553/65A GB1044246A (en) 1962-12-31 1965-05-10 Improvements in or relating to electronic servo apparatus for following the contour of line patterns
FR21719A FR1445798A (fr) 1964-06-24 1965-06-22 Lecteur électronique de courbes

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US248585A US3229100A (en) 1962-12-31 1962-12-31 Electronic servo system
US305254A US3267285A (en) 1963-08-29 1963-08-29 Variable resolution curve following apparatus
US377749A US3387138A (en) 1962-12-31 1964-06-24 Radiant energy sensitive electronic curve follower

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Publication Number Publication Date
US3387138A true US3387138A (en) 1968-06-04

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US377749A Expired - Lifetime US3387138A (en) 1962-12-31 1964-06-24 Radiant energy sensitive electronic curve follower

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US (1) US3387138A (fr)
BE (1) BE641906A (fr)
CH (1) CH411421A (fr)
DE (2) DE1205745B (fr)
FR (2) FR1393325A (fr)
GB (4) GB996509A (fr)
NL (2) NL302499A (fr)
SE (1) SE313685B (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3514753A (en) * 1966-01-12 1970-05-26 Ibm Character recognition system
US3629828A (en) * 1969-05-07 1971-12-21 Ibm System having scanner controlled by video clipping level and recognition exception routines

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1549880B1 (de) * 1967-08-29 1971-01-21 Siemens Ag Anordnung zur optischen Abtastung von Zeichen

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3229100A (en) * 1962-12-31 1966-01-11 Ibm Electronic servo system
US3245036A (en) * 1957-05-17 1966-04-05 Int Standard Electric Corp Character recognition by contour following
US3267285A (en) * 1963-08-29 1966-08-16 Ibm Variable resolution curve following apparatus
US3289004A (en) * 1963-09-03 1966-11-29 Ibm Photosensitive electronic servo apparatus for curve following

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1090890B (de) * 1958-10-15 1960-10-13 Standard Elektrik Lorenz Ag Verfahren und Anordnung zur automatischen Zeichenerkennung
FR1312707A (fr) * 1961-01-12 1962-12-21 Thomson Houston Comp Francaise Perfectionnements aux dispositifs d'identification de caractères

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3245036A (en) * 1957-05-17 1966-04-05 Int Standard Electric Corp Character recognition by contour following
US3229100A (en) * 1962-12-31 1966-01-11 Ibm Electronic servo system
US3267285A (en) * 1963-08-29 1966-08-16 Ibm Variable resolution curve following apparatus
US3289004A (en) * 1963-09-03 1966-11-29 Ibm Photosensitive electronic servo apparatus for curve following

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3514753A (en) * 1966-01-12 1970-05-26 Ibm Character recognition system
US3629828A (en) * 1969-05-07 1971-12-21 Ibm System having scanner controlled by video clipping level and recognition exception routines

Also Published As

Publication number Publication date
CH411421A (de) 1966-04-15
NL145071B (nl) 1975-02-17
BE641906A (fr) 1964-04-16
GB996509A (en) 1965-06-30
DE1205745B (de) 1965-11-25
GB1039948A (en) 1966-08-24
FR1393325A (fr) 1965-03-26
GB1008560A (en) 1965-10-27
FR1409557A (fr) 1965-08-27
DE1211009B (de) 1966-02-17
SE313685B (fr) 1969-08-18
NL302499A (fr) 1965-10-25
GB1044246A (en) 1966-09-28

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